The present invention relates to a bookmaking apparatus in a bookmaking system that aligns sheets printed by an image forming apparatus in a bundle on a tray in the proper page order and binds the sheet bundle to create a booklet.
Generally, this kind of apparatus is widely used as a terminal device of an image forming apparatus such as a printer or printing machine, to stack sheets formed with images in page order. After aligning the sheets into a booklet, a bookmaking system applies adhesive to one edge of the stacked booklet and binds the stacked booklet to a cover sheet. Of particular note, recently there are many systems that print and finish a predetermined booklet by printing predetermined information and automatically binding and covering the booklet, then cutting the edges of sheets, as an on-demand printing system, such as electronic publishing.
Such a system is proposed in Japanese Patent Application Publication No. 2004-209869 (“869”) to automatically create a booklet of sheets output from an image forming apparatus. In this publication, sheets output from an image forming apparatus are received from a discharge outlet and guided to a discharge path where they are stacked and stored in a tray equipped at a lower side of the discharge outlet. The sheet bundle stacked on the tray in a horizontal posture is turned 90 degrees and then guided to an adhesive application unit in a vertical posture for gluing. The glued sheet bundle is then folded around and glued to a cover sheet supplied from an inserter device. After adhesion of the sheet bundle and cover, sheet bundle sides not glued to the sheet bundle are trimmed to finish the booklet. The finished booklet is then stored in a stacker.
In the 869 system, at a cross-over unit comprising a path for conveying a sheet bundle and a path for conveying a cover sheet, both sheets are joined in a substantially upside-down T-shape, and when folding a cover sheet over a back side surface of the sheet bundle, it is necessary to position the sheet bundle and cover sheet with the correct posture.
Positioning of both sheets is done at a joining stage formed at a cross-over unit of both paths. In other words, when conveying a sheet bundle and positioning it at a cover sheet, a sheet bundle conveyance mechanism, e.g., a gripping conveyance mechanism, is often utilized to convey the sheet bundle in front and back directions and left and right width directions of the cover sheet. When conveying the other cover sheet, a mechanism for conveying a cover sheet fed to the joining stage in the front and back directions of the conveyance direction, and for conveying in the left and right width directions is equipped. Such a mechanism requires a complex configuration to be embedded in the area around the joining stage and as a result many bookmaking apparatuses are set to one particular sheet size.
As mentioned above, positioning the sheet bundle and cover sheet at the joining stage requires positional adjustments to both the sheet bundle and cover sheet, resulting in a complex sheet joining unit. Particularly, a folding mechanism comprising rollers for folding a cover sheet to a backside of a sheet bundle at a downstream side, results in large and complex sheet joining unit.
Therefore, the present invention positions a cover sheet in the width direction according to a sheet size upstream of the sheet joining stage and then aligning the length direction of sheets. The cover sheet is then conveyed for a predetermined amount according to the thickness of the sheet bundle. Therefore, the present invention provides a bookmaking apparatus that can accurately position a sheet bundle and cover sheet fed at cross-over directions using a simple mechanism. Furthermore, the present invention provides a bookmaking apparatus that enables the bookmaking of a wide range of sheet types that vary in size, while enabling bookmaking of sheet bundles that vary in thicknesses.